In January, Rick Kohl of Oceanside discovered that he had overpaid the state Employment Development Department by 44 cents on his quarterly personal income and unemployment insurance taxes for his corporation, Preferred Energy Services.

After some previous dealings with the agency, he decided he wouldn't go through the trouble of getting back the nominal amount.

"For 44 cents, I'll make a contribution to the state fund," Kohl said.

So that begged the question: How common is it for a company to overpay the department on those taxes, and what happens to that money?

Loree Levy, a spokeswoman for the agency, said the department does not issue dollar refunds unless an employer specifically requests it. If there's no request, the surplus amount becomes a credit toward the next balance due. The state holds on to that money interest-free.

Levy said that among the roughly 500,000 employers in California who overpaid on such taxes last year, the average credit was 33 cents. That added up to a $165,000 interest-free loan for the state agency through 2012.